title: Reduction of methylviologen-mediated oxidative stress tolerance in antisense transgenic tobacco seedlings through restricted expression of StAPX.
abstract: Ascorbate peroxidases are directly involved in reactive oxygen species (ROS) scavenging by reducing hydrogen peroxide to water. The tomato thylakoid-bound ascorbate peroxidase gene (StAPX) was introduced into tobacco. RNA gel blot analysis confirmed that StAPX in tomato leaves was induced by methylviologen-mediated oxidative stress. The sense transgenic seedlings exhibited higher tAPX activity than that of the wild type (WT) plants under oxidative stress conditions, while the antisense seedlings exhibited lower tAPX activity. Lower APX activities of antisense transgenic seedlings caused higher malondialdehyde contents and relative electrical conductivity. The sense transgenic seedlings with higher tAPX activity maintained higher chlorophyll content and showed the importance of tAPX in maintaining the optimal chloroplast development under methylviologen stress conditions, whereas the antisense lines maintained lower chlorophyll content than WT seedlings. Results indicated that the over-expression of StAPX enhanced tolerance to methylviologen-mediated oxidative stress in sense transgenic tobacco early seedlings, whereas the suppression of StAPX in antisense transgenic seedlings showed high sensitivity to oxidative stress.
authors.affiliation: College of Food and Biological Engineering, Jiangsu University, Zhenjiang 212013, China. weihongsun2009@163.com
authors.forename: Wei-Hong
authors.initials: WH
authors.lastname: Sun
authors.forename: Yong
authors.initials: Y
authors.lastname: Wang
authors.forename: Hua-Gang
authors.initials: HG
authors.lastname: He
authors.forename: Xue
authors.initials: X
authors.lastname: Li
authors.forename: Wan
authors.initials: W
authors.lastname: Song
authors.forename: Bin
authors.initials: B
authors.lastname: Du
authors.forename: Qing-Wei
authors.initials: QW
authors.lastname: Meng
mesh_terms: D000975:Antioxidants / Q000737:chemistry; D060387:Ascorbate Peroxidases / Q000096:biosynthesis* / Q000235:genetics*; D002734:Chlorophyll / Q000737:chemistry; D002736:Chloroplasts / Q000235:genetics; D004553:Electric Conductivity; D018506:Gene Expression Regulation, Plant; D006540:Herbicides / Q000737:chemistry; D018551:Solanum lycopersicum / Q000201:enzymology; D008315:Malondialdehyde / Q000737:chemistry; D016376:Oligonucleotides, Antisense / Q000235:genetics; D018384:Oxidative Stress; D010269:Paraquat / Q000737:chemistry*; D010641:Phenotype; D030821:Plants, Genetically Modified / Q000235:genetics; D036226:Seedlings / Q000235:genetics; D013312:Stress, Physiological; D014026:Nicotiana / Q000235:genetics / Q000502:physiology*
chemical_list: D000975:Antioxidants; D006540:Herbicides; D016376:Oligonucleotides, Antisense; D002734:Chlorophyll; D008315:Malondialdehyde; D060387:Ascorbate Peroxidases; D010269:Paraquat